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Jason's Neuro Block > Visual Pathways > Flashcards

Flashcards in Visual Pathways Deck (32):
1

Main Visual pathway:

GCs>optic nerve>chiasm>LGN>optic radiations>visual cortex

2

intrinsically photosensitive ganglion cells contain?

melanopsin

3

2 targets of melanopsin?

1. suprachiasmatic nucleus: circadian
2. pretectal n.: midbrain: pupil response

4

M ganglions detect? what %?

motion: 10%

5

P ganglions detect?

colour/visual acuity: 80%

6

target of most GCs?

lateral geniculate nucleus in the thalamus

7

what happens in superior colliculus?

eye movements

8

what happens in suprachiasmatic n.?

circadian rhythm

9

what happens in pretectum midbrain?

pupil responses

10

what crosses at optic chiasm?

nasal fibres of optic nerve which sense the temporal fields

11

right visual hemisphere viewed by?

left cortex

12

left visual hemisphere viewed by?

right cortex

13

what usually causes problems in the optic chiasm?

pituitary or internal carotid issues

14

what does the medial geniculate nucleus receive?

hearing signals

15

how many layers of LGN? divided into which two?

Magnocellular: 1,2 (darker, bigger)
Parvocellular: 3,4,5,6

16

Which layers in the LGN receive from which eye?

Right:2,3,5
Left:1,4,6

17

what happens to signal after LGN ?

project as optic radiation to cortex via massive white matter tracts

18

primary visual cortex is where?

1. area 17
2. occipital lobe around calcarine fissure

19

centre of the visual field is where in the lobe?

most occipital part of the visual cortex

20

unilateral vision loss lesion is most likely?

before the optic chiasm

21

bitemporal vision loss lesion is most likely?

optic chiasm

22

bilateral field loss, lesions is most likely?

after the chiasm

23

when do you get macular sparing?

unique feature of vascular problem in the visual cortex

24

how many intrinsically photosensitive ganglion cells per retina?

~5000

25

intrinsically photosensitive ganglion cells contain what?

melanopsin: like in invertebrates

26

what happens when melanopsin is hit with light?

depolarizes intrinsically photosensitive ganglion cells

27

what non vision info do intrinsically photosensitive ganglion cells transmit? 5 things:

1. circadian rhythm (hypothalamus)
2. sleep regulation
3. pupil responses
4. general light levels
5. light allodynia

28

photophobia during migraine comes how?

pain signals from dura via trigeminal end up at posterio nucleus of thalamus and intrinsically photosensitive ganglion cells also project there

29

blind people who have retinas get photophobia?

yes

30

Pupil response pathway

optic nerve>pretectal nucleus>edinger-westphal>CNIII>sphincter pupillae

31

where do intrinsically photosensitive ganglion cells with melanopsin project to in the pupil repsonse?

optical pretectal nucleus

32

where is suprachiasmatic nucleus?

hypothalamus, and affected by intrinsically photosensitive ganglion cells